1. Field of the Invention
The present invention relates to a production process for a semiconductor apparatus, and in particular to a production process for a semiconductor apparatus in which there is no danger of particle generation, and consequently no danger of associated problems resulting from the presence of particles, such as shorting, and which as a result, is capable of producing improved product yields, good product quality stability and improved product reliability.
2. Description of the Background Art
In conventional production processes for semiconductor apparatus such as IC, LSI and VLSI, dry etching is used for the patterning of wiring films, semiconductor films, insulating films and interlayer films.
FIG. 4 and FIG. 5 are process diagrams showing one example of a conventional production process for a semiconductor apparatus, in which wiring formed from a conductive material such as a metal is formed on top of an N-type silicon substrate (a semiconductor substrate).
First, as shown in FIG. 4A, a sputtering method or a vacuum deposition method is used to form an aluminum layer 2 on an N-type silicon substrate 1.
Next, as shown in FIG. 4B, a spin coating method is used to apply a negative type photoresist to the top of the aluminum layer 2, forming a resist layer 3.
Subsequently, as shown in FIG. 4C, a photomask 4 with a predetermined mask pattern is positioned on top of the resist layer 3, and by then irradiating the resist layer 3 with ultraviolet radiation 5 through the photomask 4, the mask pattern of the photomask 4 is burnt into the resist layer 3. The photomask 4 has openings 4a only in those sections which correspond with the wiring of the N-type silicon substrate 1, and consequently within the resist layer 3, only those sections of the resist 3a which correspond with the wiring on the N-type silicon substrate 1 are irradiated by the ultraviolet radiation 5 and are hardened to become insoluble in the developing solution, whereas the remaining sections of the resist 3b are not subjected to the ultraviolet radiation 5, and are consequently soluble in the developing solution.
Next, as shown in FIG. 4D, the resist layer 3 is developed, and the covered sections of the resist 3b are dissolved in the developing solution. As a result, the resist layer 3 is reduced to only those resist sections 3a corresponding with the wiring pattern.
Subsequently, as shown in FIG. 5A, the aluminum layer 2 is subjected to dry etching 6 using a plasma, with this resist layer 3 functioning as a mask, and within the aluminum layer 2, only those sections of aluminum 2a which correspond with the wiring are left on the substrate, whereas the remaining sections of the aluminum 2b are removed. Here, because those sections of the aluminum 2b outside the wiring are removed, the surface of the N-type silicon substrate 1 is exposed within these regions 2b where the aluminum has been removed, as shown in FIG. 5B.
Next, as shown in FIG. 5C, the resist layer 3 is removed. As a result, from the aluminum layer 2, only those sections of the aluminum 2a corresponding with the wiring remain on the surface of the N-type silicon substrate 1, and this remaining aluminum 2a forms a predetermined wiring pattern 7.
However, in the conventional production process for a semiconductor apparatus described above, when the aluminum layer 2 is subjected to dry etching 6, once gasified unwanted matter and particles (unwanted matter) once adhered to the internal walls of the etching apparatus can adhere to the exposed surface of the N-type silicon substrate 1 again, resulting in a danger of potential shorting of the wiring 7.
In addition, in dry etching 6, because there are an extremely large number of gas varieties used as etchants, the etching process can become quite complicated. Furthermore, the apparatus must be changed for each gas variety, meaning the number of apparatuses used is also extremely large, and this is a factor in increasing the production costs.